When volcanic rock and large iron deposits collide with the eroding powers of the ocean, red sand beaches are born. There are three major red sand beaches in the world: Kokkini Beach in Greece, Kaihalulu Beach in Hawaii, and one in the Galapagos.
Grímsvötn is a volcano in South-East Iceland. It is in the highlands of Iceland at the northwestern side of the Vatnajökull ice-cap. The caldera is at at an elevation of m ft). Beneath the caldera is the magma chamber of the Grímsvötn volcano.